The invention described herein may be manufactured, used and licensed by or for the Government for governmental purposes without the payment to us of any royalties thereon.
Remote imaging systems are in use in many applications ranging from convenience store monitoring cameras to sophisticated imaging systems on satellites in space. Such systems typically consist of an imaging sensor comprised of light-gathering optics, a detector array and support electronics that produces an electronic video signal that is transmitted to a remote site for human operator viewing and recording. The imaging sensor is often rotated about one or more axes (usually using a set of gimbals) or translated in space to view an area that is larger than that covered by the sensor""s optical field of view. In many systems the gimbals are controlled by gyroscopes to isolate the base motion of the sensor platform from the image, thus providing a stable image for the operator. Often, the sensor optical system contains a zoom lens or switchable elements that allow the field of view to be changed for greater resolution or for a larger field of view coverage. By these means the operator is able to view different portions of the observable space (commonly called the xe2x80x9ctarget spacexe2x80x9d or xe2x80x9ctarget areaxe2x80x9d) at the resolutions needed to detect and recognize items of interest. In most applications, the images received from the remote sensor are recorded on videotape for later viewing and/or processing by observers at different remote sites.
Existing remote imaging systems lack the capability to produce much higher resolution and larger field of view combinations without the use of expensive and heavy switchable optical elements and gimbals. Such a combination of concurrent high resolution and large field of view is desired without significant increases in transmission system bandwidth or in degradation of image stability. Further, there is a need to be able to record the images in such a manner that any portion of the imaged target space is viewable almost instantly and can be sent to observers at remote sites. Lastly, all of these needs should be met at a cost that is affordable and scalable, as the application requires.
The Remote Mosaic Imaging System having High-Resolution, Wide Field-of-View and Low-Bandwidth, hereinafter referred to as the xe2x80x9cRemote Mosaic System,xe2x80x9d utilizes a plurality of remote sensors to create a plurality of images. Readily available and inexpensive commercial imaging sensors, such as the sensors commonly used in hand-held camera recorders (xe2x80x9ccamcordersxe2x80x9d) can be used to create input images without zoom lenses, field of view-changing mechanisms or gimbals. The use of such sensors significantly decreases the cost of the system while greatly increasing the capabilities of the imaging system to cover virtually any target space with virtually any desired resolution.
Furthermore, as described in detail below, the xe2x80x9cRemote Mosaic Systemxe2x80x9d uses image frame synchronization and multiplexing to reduce the bandwidth needed to transmit the plurality of images to a remote location. Because the sensors can be physically mounted on the same platform, the image relationships from one sensor to an adjacent sensor are accurately fixed, thereby easing the subsequent mosaic-processing burden.